Downhole Sand-Production Evaluation for Sand-Management Applications
- Laksmono Swarnanto (PTTEP Thailand) | Sittichod Srihirunrusmee (PTTEP Thailand) | Pipat Lilaprathuang (PTTEPI Myanmar) | Nawapol Panmamuang (PTTEP Thailand) | Katha Wuthicharn (PTTEPI Myanmar) | Parijat Mukerji (Schlumberger France) | Tanabordee Duangprasert (Schlumberger Thailand) | Toon Puttisounthorn (Schlumberger Thailand) | Pascal Millot (Schlumberger Malaysia) | Ezequiel Saavedra (Schlumberger France) | Maxime Nollet (Schlumberger France)
- Document ID
- Society of Petrophysicists and Well-Log Analysts
- Publication Date
- August 2018
- Document Type
- Journal Paper
- 489 - 495
- 2018. Society of Petrophysicists & Well Log Analysts
- 6 in the last 30 days
- 211 since 2007
- Show more detail
Sand production is a serious problem in offshore gas assets in Thailand and Myanmar. It is damaging downhole completions, subsea equipment and surface facilities, which increases the risk of catastrophic failures. Sand-production management is a complicated issue involving all aspects of well deliverability that cannot be addressed by a one-size-fits-all approach. An important element of controlling the extent of sand production is managing the pressure drawdown and production rate throughout the life of a well. Sand monitoring is a key to production optimization, while also enabling geomechanical model calibration and assessing the need for remedial work.
Log-based sand-prediction models are established for some gas wells in Thailand and Myanmar to predict the sand production in similar wells in the area. Surface sand detectors are also installed to optimize production by limiting pressure drawdown and achieve sand-free rate production. However, pipe erosion continues to occur and results in flowline replacement after a few years of production.
It is very important to get a reliable downhole measurement of sand production zone-by-zone to be able to calibrate the models, confirm the sand-free rate production, effectively manage the choke size during production, and plan remedial work to reduce or eliminate the sand production.
Conventionally, industry is using nonintrusive measurements, such as ultrasonic surface detectors or the previous generation of downhole sand-detection tools. These methods do not provide a complete picture of sand production and are not able to deliver quantifiable direct measurement of sand-production rate. Road noise or turbulence effect can be a challenge in some well conditions as well.
The latest-generation of downhole sand-detection tool records the energy level of individual sand-grain impacts, which are converted to sand-production rate per producing zone. This tool was run on wireline during multirate production logging (PL) to identify zonal sand entry, maximum sand-free rate (MSFR), maximum allowable-sand rate (MASR) and zonal fluid-entry profile to optimize pressure drawdown. The results from the downhole sand detector can be used to calibrate the surface ultrasonic sand measurement.
It is the first time that a downhole detector was able to count the number of sand particles and their energy from each producing interval. In one of the examples, 603 counts/sec of sand grains were detected from one of the perforation intervals. This perforation was producing gas and water, as confirmed from PL measurements. This is a crucial piece of information for well optimization under sand-free rate production. A straddle patch was installed to isolate this zone and enable the well to flow at its maximum capability without sand production.
Understanding the sand and reservoir fluid production allows the operator to optimize the pressure drawdown to ensure the maximum sand-free rate, isolate sand-production zones and enable calibration/fine-tuning of the geomechanical model by using actual dynamic downhole data. This new technology enables four-phase production logging (oil, water, gas, and sand).
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